Ionic Compounds and Naming

Chapter 4.10,4.11 and 5

Combining Elements

When we begin combining elements we make compounds.

Two types◦Non-metal and metal◦Non-metal and non-metal

Each type has unique physical and chemical properties

Look at non-metal and metal in detail now and non-metal and non-metal later

Ionic compounds

A metal and a non-metal combination make an ionic compound◦Each element or polyatomic group is an ion◦What makes an ion?

An ion is a charged particle (positive or negative) Difference between protons and electrons in an

element◦Ca vs Ca+2 (Ca+2 has 2 less electrons than Ca)

The number of valence electrons determines the type of ion formed◦Trying to reach noble gas state

Lose or gain electrons to reach magic number 8◦Valence electrons are known by group number

Main group elements only These atoms follow a pattern down the column

Valence electrons vs charge

Practice

How many valence electrons do the following elements have?

What would their charge be?

◦K Mg Al C◦P O Br Ar

◦Do you see any pattern to the charges? Metals make positive ions (cations) Non-metals make negative electrons (anions)

Making ionic compounds

First determine the charge on the cation and the anion.

Then adjust the number of cations and anions you need to make the compound neutral.

All ionic compounds are overall neutral; that is when you add up all the charges the sum is zero

Making ionic compounds

NaCl is made with Na+1 and Cl-1MgO is made with Mg+2 and O-2

Na2O is made with 2 Na+1 and O-2

MgCl2 is made with Mg+2 and 2 Cl-1

Practice

Combine K and F to make a neutral compound◦ K makes a K+1 ion◦ F makes a F-1 ion◦ Need one of each to make the ionic compound neutral◦ KF

Put the following elements together to make ionic compounds

Be and FLi and SBa and NK and AsCs and C

Transition metals

What about the elements in-between group II and III?◦Called transition metals because they can

make more than one positive charge◦On our tables you can tell by the small black

number above the symbol…..

Practice with transition metals

Cu II and SW IV and OPd II and NCr III and Si

Polyatomic Ions

Some ions are actually a group of elements combined together◦Can not be broken apart◦Act as one unit

These are known as polyatomic ions

◦See handout

Naming Binary Compounds

Naming Binary Compounds

We can easily name binary compounds both ionic and covalent (non-metals)

◦Non-metals and metals use type I and II

◦Non-metals and non-metals use type III

Naming Binary Ionic Compounds

Type I◦Metal bonded to non-metal◦Metal always listed and named first

No changes in the metal name◦Metals only make ONE ion (known as simple

metals)◦Anion is listed second

Use the root of the name and add –ide◦Hydrogen becomes hydride◦Halogens remove –ine and add –ide◦Oxide, nitride, sulfide

◦ NaCl is sodium chloride

Type II◦use transition metals

Cation is first again and anion is changed the same as type I

The difference is that we need to designate the charge of the transition metal with a Roman Number

USE THE ANION TO DETERMINE THE CHARGE OF THE CATION!!!

CuO◦Oxygen is -2◦The compound must be neutral◦So the copper (Cu) must be +2◦The compound is named copper II oxide

Practice

Name the following ionic compounds:

CaF AlCl3 MgI2

CuBr2 Al2O3CrCl3

Fe2O3 FeO FeCl3

The number of atoms has no influence on the name for type I and II

Polyatomic Ions

Polyatomic ions just use their name

K2SO4 would be potassium sulfate

NH4NO3 would be ammonium nitrate

Co(NO2)2(NH4)3N

Type III◦Non-metal to non-metals

NUMBER OF ATOMS IS IMPORTANT FOR TYPE III

Use prefixes to determine the number of atoms in the name

Same naming scheme as type I Use entire name for 1st element -ide for 2nd Add prefixes for multiple atoms

◦Note: mono- is never used on 1st element

Prefixes◦1 – mono◦2 – di◦3- tri◦4- tetra◦5- penta◦6- hexa◦7- hepta◦8- octa◦9- nona◦10- deca

Practice

CCl4 would be carbon tetrachlorideN2O2 would be dinitrogen dioxide

PCl5 P4O6

N2O5 SF6

CO NO2

Naming Acids

Acids are a special group of binary compounds and have their own naming rules.

All acids begin with H and are dissolved in water

Acids without oxygen◦Use root of anion and add –ic and acid◦HCl is hydrochloric acid

Acids with oxygen◦-ite becomes –ous◦-ate becomes –ic◦H2SO3 is sulfurous acid◦H2SO4 is sulfuric acid

Naming acids

If the anion ends in –ide◦Start with hydro◦Use the root of the anion◦Add –ic acid to the end

If the anion ends in –ate◦NO HYDRO◦Use the root or slightly more and add –ic acid

If the anion ends in –ite◦NO HYDRO◦Use the root or slightly more and add –ous acid

Practice

Name these acids

HF

HNO3

H3PO4

Reversing the process

Write the formulas from these names:

Nitric acidPotassium sulfideSodium carbonateDinitrogen pentoxide